David Walsh Blog

  • By

    How to Open an App from Anywhere on Mac Command Line

    Many engineers like myself live in the command line, and perform actions from command line that most others would click an icon for. I've always found opening apps from command line on Macs painful. You need to references the Applications directory, add .app to...

  • By
    How to Create a Diff of Two Images

    When I was a child, I loved looking for Waldo in the "Where's Waldo?" book series. These days I'm a sucker for TMZ's "What's the Big Frigin Difference" images, where TMZ slightly changes an image and you have to spot the differences between the two.

  • By
    5 Web Design Trends for 2023 That You Should Pay Attention To

    The start of a new year is usually a time when we start looking for ways to make something a little better. That something could be our life, work, or what we produce. Web designers, for example, might look for ways to make their designs more...

  • By
    fetch with Timeout

    A few years back I wrote a blog post about how write a fetch Promise that times out. The function was effective but the code wasn't great, mostly because AbortController , which allows you to cancel a fetch Promise, did not yet exist. With...

  • By
    Customizing HTML Form Validation

    Form validation has always been my least favorite part of web development. You need to duplicate validation on both client and server sides, handle loads of events, and worry about form element styling. To aid form validation, the HTML spec added some new form attributes...

  • By
    How to Determine a JavaScript Promise’s Status

    Promises have changed the landscape of JavaScript. Many old APIs have been reincarnated to use Promises (XHR to fetch, Battery API), while new APIs trend toward Promises. Developers can use async/await to handle promises, or then/catch/finally with callbacks, but what Promises don't tell...

  • By
    Detect XR Support with JavaScript

    A few years ago I wrote an article about how to detect VR support with JavaScript. Since that time, a whole lot has changed. "Augmented reality" became a thing and terminology has moved to "XR", instead of VR or AR. As such...

  • By
    Document.elementFromPoint

    Reacting to events with JavaScript is the foundation of a dynamic experiences on the web. Whether it's a click event or another typical action, responding to that action is important. We started with assigning events to specific elements, then moved to event delegation...

  • By
    Detect Browser Bars Visibility with JavaScript

    It's one thing to know about what's in the browser document, it's another to have insight as to the user's browser itself. We've gotten past detecting which browser the user is using, and we're now into knowing what pieces of the browser UI users are...

  • By
    JavaScript print Events

    Media queries provide a great way to programmatically change behavior depending on viewing state. We can target styles to device, pixel ratio, screen size, and even print. That said, it's also nice to have JavaScript events that also allow us to change behavior. Did...

Popular Features

  • By
    39 Shirts – Leaving Mozilla

    In 2001 I had just graduated from a small town high school and headed off to a small town college. I found myself in the quaint computer lab where the substandard computers featured two browsers: Internet Explorer and Mozilla. It was this lab where I fell...

  • By
    Interview with a Pornhub Web Developer

    Regardless of your stance on pornography, it would be impossible to deny the massive impact the adult website industry has had on pushing the web forward. From pushing the browser's video limits to pushing ads through WebSocket so ad blockers don't detect them, you have...

  • By
    Welcome to My New Office

    My first professional web development was at a small print shop where I sat in a windowless cubical all day. I suffered that boxed in environment for almost five years before I was able to find a remote job where I worked from home. The first...

  • By
    How to Create a RetroPie on Raspberry Pi – Graphical Guide

    Today we get to play amazing games on our super powered game consoles, PCs, VR headsets, and even mobile devices.  While I enjoy playing new games these days, I do long for the retro gaming systems I had when I was a kid: the original Nintendo...

  • By
    Conquering Impostor Syndrome

    Two years ago I documented my struggles with Imposter Syndrome and the response was immense.  I received messages of support and commiseration from new web developers, veteran engineers, and even persons of all experience levels in other professions.  I've even caught myself reading the post...

  • By
    Being a Dev Dad

    I get asked loads of questions every day but I'm always surprised that they're rarely questions about code or even tech -- many of the questions I get are more about non-dev stuff like what my office is like, what software I use, and oftentimes...

  • By
    JavaScript Promise API

    While synchronous code is easier to follow and debug, async is generally better for performance and flexibility. Why "hold up the show" when you can trigger numerous requests at once and then handle them when each is ready?  Promises are becoming a big part of the JavaScript world...